Abstract
Terbium and europium co-doped Sr 8 ZnY(PO 4 ) 7 phosphors are successfully prepared through a high temperature solid-state reaction (SSR). The crystal structure of the as-prepared samples was identified to be Sr 8 ZnY(PO 4 ) 7 (SZYP) pure phase by an X-ray powder diffraction technique. Under near-ultraviolet light excitation (378 nm), the SZYP:Tb 3+ and SZYP:Eu 3+ phosphors show green and red emission peaking at 545 and 618 nm, respectively. Moreover, an effective energy transfer process from Tb 3+ to Eu 3+ could be verified by the concentration dependence of emission intensity and lifetime. The energy transfer mechanism between Tb 3+ and Eu 3+ is determined to be governed by dipole-dipole interactions. The internal quantum efficiency (IQE) is evaluated to be as high as about 91%. The temperature-dependent spectra indicate that the SZYP:Tb 3+ ,Eu 3+ phosphor shows a high thermal stability. Furthermore, the as-fabricated white LED devices exhibit an excellent correlated color temperature (CCT) of 3223 K, a color rendering index (R a ) of 85.8 and a luminance efficiency of 37.4 lm W -1 . All results imply that the SZYP:Tb 3+ ,Eu 3+ phosphors have a great potential for application in white LEDs.
Original language | English |
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Pages (from-to) | 2927-2935 |
Number of pages | 9 |
Journal | Journal of Materials Chemistry C |
Volume | 7 |
Issue number | 10 |
DOIs | |
Publication status | Published - 1 Jan 2019 |